1. Technical Field
The present invention relates to a method of preparing a drilling fluid and lube base oil using biomass-derived fatty acid. More particularly, the present invention relates to a method of preparing high-quality lube base oil, including hydrogenating a fatty acid mixture derived from biomass of biological origin so as to be converted into fatty alcohol, which is then dehydrated to give a linear internal olefin (LIO), which is then oligomerized to give olefinic lube base oil, followed by hydrofinishing to remove the olefin, yielding high-quality lube base oil (e.g. Group III or higher lube base oil). The linear internal olefin, which is produced during such processes, may be utilized as a drilling fluid.
2. Description of the Related Art
Although oil-based energy has facilitated the development of human society, it suffers from problems including finiteness of resources, regional disparities, environmental pollution, etc., and thus thorough research into fully/partially replacing oil resources with biomass is ongoing.
The term “biomass” broadly refers to any material of biological origin, and narrowly refers to materials mainly derived from plant sources such as corn, soybeans, linseed, sugarcane and palm oil, and may extend to all living organisms, or by-products of metabolism, which is part of the carbon cycle.
Research into the production of high-value-added materials from biomass has been extensively and intensively carried out since the 1970s, but industrially applicable independent examples have not yet arisen. This is considered to be due to certain problems with biomass.
First, biomass resources are limited. Although too much emphasis has been placed on oil resources, they are currently present in amounts that are able to satisfy the global demand for energy and chemicals. Compared to oil resources, biomass, on which less emphasis is laid, requires additional production procedures, and is thus produced at a much lower level.
Second, biomass is not price-competitive. Biomass is produced on the premise of consumption, and thus cheap surplus biomass is difficult to find as a feed for replacing oil resources.
Third, there is difficulty in ensuring that a sufficient amount of biomass is available. Whereas oil resources are produced from preexisting oil deposits in specific areas, thus having no problems related to additional resource yield, biomass typically requires a large area under cultivation and thus it is difficult to ensure the production of biomass in sufficient amounts to serve as a resource to replace oil.
Finally, products using biomass are conventionally limited to inexpensive materials such as gasoline or diesel, making it difficult to propose independently commercially available models without political support.
However, techniques for overcoming the above limitations with improvements in biomass production are being devised these days. In particular, crude palm oil (CPO) and soybean oil (SBO), presented as surplus biomass, are globally produced in amounts on the order of millions of tons, and amounts that are able to be ensured on the open market are approximately 1 million tons or more. Furthermore, as the production amount thereof increases, price volatility is reduced, and purchase on the open market becomes possible. Also, crude palm oil is receiving attention as an alternative to oil-based products because the availability of large amounts thereof can be ensured and its price is stable on the open market. Furthermore, crude palm oil is composed of 90˜95% triglyceride, and the ratio of C16 and C18 carbon chains of triglyceride approximates 45:55 (by weight). A material corresponding to 5˜10 wt %, which is the remainder of crude palm oil other than triglyceride, is composed of C16 and C18 fatty acids, containing about 10% mono- or di-glyceride. Triglyceride, which is selectively separated through refinement of crude palm oil, is referred to as RBD (Refined Bleached Deodorized) palm oil. As such, the fatty acid and mono- or di-glyceride amounting to about 5˜10 wt %, which were removed, may be referred to as a palm fatty acid distillate (PFAD).
Currently, the amounts of crude palm oil and palm fatty acid distillate that can be purchased on the open market are about 1 million tons and about 4 hundred thousand tons, respectively. In this regard, the fatty acids that constitute triglyceride and palm fatty acid distillate are illustrated in FIG. 1. Also, the compositions of the carbon branches for crude palm oil (CPO) and palm fatty acid distillate (PFAD) are shown in Table 1 below.
TABLE 1Fatty acidCPO1 (wt %)PFAD2 (wt %)14:0 Myristic0.5~5.90.9~1.516:0 Palmitic32~5943~5116:1 Palmitoleic<0.6—18:0 Stearic1.5~8.04~518:1 Oleic27~5233~4018:2 Linoleic5.0~14  9~1118:3 Linolenic<1.50.2~0.620:0 Eicosanoic<1.0—1composed mainly of triglyceride2composed mainly of fatty acid
Compared to fuels, models for use in the commercial preparation of high-value-added products, such as lube base oil, from biomass have been proposed. For example, the production of Group III lube base oil from a feed containing 50% or more of an unsaturated compound via oligomerization, deoxygenation and isodewaxing (IDW) is known (e.g. U.S. Pat. Nos. 7,459,597 and 7,888,542).
The aforementioned techniques are mainly utilized to polymerize olefins present in biomass. To attain high reaction activity, the amount of olefin in a feed is required to be 50% or more, and naphthene-based lube base oil containing about 72% naphthene is obtained by random polymerization. In particular, isodewaxing is performed to improve the fluidity of lube base oil. Also, techniques for preparing lube base oil from fatty acid via pre-hydrotreatment, ketonization, hydrodeoxygenation (HDO) and isodewaxing are known (e.g. U.S. Pat. No. 8,048,290, etc.). Thereby, the yield of the product (Group III lube base oil) relative to the feed (fatty acid) is mentioned to be about 36%.
In addition, a process of preparing Group V lube base oil corresponding to ester-based lube base oil and 1-decene as the feed for poly alpha olefin (PAO) from triglyceride is known (U.S. Patent Application Publication No. 2012/0115762). This process includes metathesis, oligomerization, and hydroisomerization. As such, in order to ensure economic benefits, it is important to increase the proportion of C18:1, and there is a need to suppress the inactivation of precious metal catalysts and the collapse of ester structures in the hydrogenation for the skeletal isomerization of ester.